Maybe you didn't notice, but yesterday was International Anti-Tweet Day. Twitter, the microblog most people either love or hate, disappeared from the Internet for a few hours yesterday morning, then popped in and out for most of the afternoon.

As MediaJobsDaily put it:

Twitter wasn't just down, it was so down that you didn't even see a Fail Whale when you tried to load the page. Down and dirty down. Downer than down. That's how down it was.

But this time Twitter didn't go down for the usual reason: being unable to keep up with the volume of tweets. This whale of a fail was due to a deliberate attack that also affected Facebook, Live Journal, and Google.

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Today security experts are still scratching their heads over why the attacks happened. IT Harvest's Richard Stiennon suggested hackers were steamed that Twitter had stolen the shine from their own preferred methods of micro-interaction, IRC and ICQ. (Richard, I love ya, but ... hacker jealousy? Really?)

AVG's Roger Thompson thought white-hat vigilantes launched the attack to point out the dangers of botnets (because there have only been, oh, a few thousand examples of this already). He also thinks the attacker was the same one who's been pelting U.S. and South Korean government sites with malicious packets. (Damn. I knew I shouldn't have tweeted those snarky jokes about Kim Jong-Il. My bad.)

Those jokers over at eSarcasm also list 22 other reasons why Twitter may have failed. I think they may need to adjust their meds.